It has previously been known to use cooling fans to supply cooling air for the engines of vehicles. In certain military vehicles, particularly track-laying vehicles designed to ford rivers and streams, the engine compartment is "wet." That is, when the vehicle fords deep water the engine compartment fills with water, thereby submerging the engine and cooling fans. In this situation, if the fans were not disengaged they would attempt to pump the water at the same rate for which they were designed to pump air. Such a condition would produce a severe over-torque condition that would likely result in failure. For example, if the torque transfer device were allowed to slip under full load, all of the fan drive power would be convened to heat which would readily cause the clutch to fail. To obviate that result, prior known arrangements require that the crew take some affirmative steps to disconnect the fans before the engine compartment is flooded.